This invention relates to thermosetting polymers prepared from methylated pyridines or pyrazines and hydroxy aromatic mono-aldehydes.
In the aerospace and/or aircraft industry there is a need for light weight fire resistant polymeric composites for interior and exterior use. A recent development in this critical area was the discovery that composites based on polystyrylpyridines are useful in this field of endeavor. The key patents are outlined below.
It is known from U.S. Pat. No. 3,994,862 that polystrylpyridine thermosetting prepolymers and cured polymers can be obtained by reacting methylated pyridines and aromatic dialdehydes.
U.S. Pat. No. 4,163,740 discloses the preparation of solutions of polystyrlpyridines in various organic solvents such as ethyl acetate, propanol, and methylethylketone.
U.S. Pat. No. 4,362,860 discloses related polystyrylpyridines terminated with vinyl pyridine.
Bramsch, Chemische Berichte 42:1193-97 (1909) discloses the reaction of methylated pyridines and salicylaldehyde to prepare monomeric hydroxy methyl stilbazoles.
Franke, Chemische Berichte 38:3724-28 (1905) discloses the reaction of methylated pyrazines with salicylaldehyde to prepare related monomeric compounds.
Related monomeric stilbazole compounds are also disclosed by Chiang et al. J. Org. Chem. 10:21-25 (1945). In each of these articles there is no disclosure of polymers.